Blasting cartridge



.June 15, 1937.

A. HARRIS BLASTING CARTRIDGE Original Filed Aug. 5, 1933 Patented June 1937 BLASTING CARTRIDGE Allyn Harris, Wheaton, Ill., assignor to Safety Mining Company, a corporation of Illinois Application August 5, 1933, Serial No. 683,789 Renewed November 26, 1934 18 Claims. (Cl. 102-6) under appropriate conditions, thus venting the chamber 6 to the atmosphere. A check valve IS on the valve rod I4 is provided to cooperate with a series of charging passages formed in the plunger it, the operation of which will be more This invention relates to an improvement in blasting cartridges particularly to that type in which a charge of high pressure air or other gas may be introduced in work performing condition 5 and may be subsequently released or discharged from the cartridge at will.

The object oi the invention is to provide an improved mechanism within a cartridge of this type adapted to receive a charge of potential energy and to effect the discharge thereof at any desired time and particularly in relation to any desired attained value of a charge of potential energy.

Other objects and advantages of the invention will appear in connection with the following detailed description.

Referring to the drawing, the single figure is a view in longitudinal section through a blasting cartridge embodying by way of illustration the principles of the present invention.

The body of the cartridge I is provided with a charge receiving chamber'2 which may be of any desired volumetric capacity. The ends of this body are internally threaded as shown for the reception of the correspondingly threaded ends of discharge and terminal caps 3 and 6 respectively. The discharge cap 3 is provided with a plurality of dischargeoriilces 5 through which a charge of potential energy contained within the main chamher 2 of the cartridge may escape into the material to be broken down by the cartridge.

Terminal cap 4 is provided with a cylindrical chamber 6 into which high pressure air or other forms of potential energy may be introduced through a suitable supply pipe I, fitting 8 and supply passage 9. In this connection it will be observed that there is provided in terminal cap 6 an axial bore 62 which communicates with the chamber 6 but which is eiiectively sealed from the l atmosphere by means of a suitable metal or fibre disc ii and a sealing nut ill. the latter having threaded connections with terminal cap 6.

A plunger i3 is slidably disposed within the cylindrical bore 6 of the terminal cap and this plunger is carried by one end of a valve rod M which extends throughout the length of the main chamber 2 of the cartridge and carries at its opposite end a valve member i6 designed to have sealing engagement as indicated at i! with the inner end of discharge cap 3. The end of rod ill on which plunger i3 is mounted also carries a chisel ii the end of which extends slightly into axial bore l2 when valve It is in sealing engagement with the end of the discharge cap. The

'oopurposeofthlschiselistopuncturethediscii particularly described hereinafter.

For the purposes of explanation we may assumethat the cartridge as above described has been positioned in a suitable drill hole formed in the face of coal to be broken down and that it is ready to perform its intended work. The supply pipe I having been connected to the cartridge in the manner indicated on the drawing may be extended back to a remote point and there connected to a suitable source of high pressure air or other form of potential energy.

It should be mentioned in this connection that such source of potential energy may be in the form of a generator such as an air compressor or in the form of a receiver containing a considerable quantity of such potential energy. Having connected the supply pipe 1 to a source of potential energy and opened a suitable valve permitting such potential energy to flow from the source to the cartridge, the following results occur. For convenience we will assume that the form of potential energy is compressed air of a pressure ranging from 5,000

to 10,000 pounds per square inch.

high pressure air into the chamber 6 results first in immediately moving the plunger i3 and valve rod M attached thereto'in a direction to bring the valve [6 into firm sealing engagement with the ends of the discharge cap 8 as indicated at ll. This action is followed immediately by the bulld ing up of pressure within chamber ii suillciently to overcome the spring pressed check valve i8 thereby permitting a flow of high pressure air from the chamber 6 into the main chamber 2 of the cartridge. There will, of course, be a slight differential between the pressures existing in chambers 2 and B, that in chamber 6 preponderlng slightly during the entire charging operation. When the pressure in chamber 2 has reached a desired value, which may be readily determined by a suitable pressure gauge located in the supply line 1 adjacent to the source of supply, the control valve positioned at the source of supply may be cut ofi to discontinue the flow of high pressure air into chamber 6. When the flow of air into chamber 6 has been stopped the check valve l8 will immediately close thereby preventing the passage of air from chamber 6 to chamber 2 and vice versa.

Under these conditions valve IE will be mainwith the end I exposed to the pressure existing in chamber 6 is substantially greater than the cross sectional area of plunger l3 which is exposed to the pressure existing in chamber 2.

In order to efiect the discharge of the cartridge which has been charged as described above it is merely necessary to relieve the pressure existing in chamber 6 thereby bringing about a reversal of the diiferential pressure conditions as described above. In other words with the pressure in chamber 6 substantially or entirely relieved the pressure existing in chamber 2 acting upon the face'orplunger 53 which is exposed to such pressure wlll resul 1' in an immediate axial movement of the plunger and valve rod in a direction away from the discharge cap. The pressure in cham-= .ber 6 may be conveniently relieved by merely openings. suitable valve at or adjacent the source of supply and serving to vent the supply pipe I to the atmosphere. This will result in an immediate drop in pressure within the chamber 6 which will cause actuation of the plunger and valve mecha- 5 nisms as described above. In order to secure complete and rapid depletion of the pressure in chamber 6 advantage is taken of the initial movement of plunger 13 and its associated valve rod to shear out the disc II by means of the chisel I5. Thus immediately upon the venting of pipe I to the atmosphere the pressure of chamber 6 will drop sufiiciently to cause a rapid axial movement of plunger l3 and the valve rod and by reason of the fact that this movement is actuated by a very 5 considerable pressure diiierential as between chambers 2 and 6 there is ample force to bring about the rupturing of disc H by means of the chisel l5 carried by the valve rod. The rupturing oi disc I I serves to greatly accelerate the escape of air from chamber 6.

' Experience has developed the fact that the pressure in chamber 6 must be dissipated very rapidly in order to prevent alternate opening and closing of the valve it which, of course, under certain conditions may be undesirable. Thus if the escape of pressure from chamber 6 is relatively slow the initial movement of plunger l3 which, of course, is inevitable by reason of a positive differential in pressures, may be reversed due to a more rapid drop in pressure within chamber 2 resulting from the escape of large volumes of high pressure air irom that chamber through the discharge cap. However, by means of the auxiliary venting arrangement shown and described there is accomplished a positive opening of the discharge valve and the ability to retain this valve in open position until the entire charge-contained in chamber 2- has been exhausted. While I have in this application specifically described one form which my invention may assume in practice, it will be understood that this form of the same is shown for Purposes of illustration, and that the invention may be modified and embodied in various other forms without departing from its spirit or the scope of the appended claims.

I claim:

1. A material breaking. device of the character described comprising a cartridge embodying a charge receiving chamber having a discharge orifice, a diilerential valve mechanism designed to cbntrol said discharge orifice, a control pocket for governing the action of said diflerential valve mechanism, means for venting said control pocket to the atmosphere, and means consequent upon movement of the difierential valve mechanism for accelerating the venting of said control pocket.

2, A material breaking device comprising a cartridge having a discharge orifice, a difierential valve controlling said orifice, a control chamber governing the action of said diiferential valve, means for initiating the opening movement of said diiferential valve and means consequent upon such movement for venting said control chamber to the atmosphere.

3. In a blasting cartridge, a container having a charge receiving chamber and a discharge orifice, means for controlling said discharge orifice, to preclude or effect charge release, means for governing the action of said control means providing control thereof independent of the existence of any particular blasting pressure in said chamber, means for initiating the operation of said control means to effect opening movement of the latter, ani means consequent upon such movement for accelerating actuation of said governing means quickly to open widely said control means.

4. In a blasting cartridge, a container having a charge receiving chamber and a discharge opening through which the charge may be released, a differential valve responsive solely to charge pressure conditions within said container for controlling said discharge opening, means for effecting initiation of opening movement of said differential valve, and means automatically operative upon initiation of opening movement of said valve for effecting rapid movement of said valve into its wide open position:

5. In a blasting cartridge, a container having a charge receiving chamber and a discharge opening through which the charge may be released, a difierential valve responsive solely to charge pressure conditions within said container for controlling said discharge opening, means controllable from a remote point for providing charge pressure conditions efiecting initiation of opening movement of said differential valve, and means automatically operative upon initiation of opening movement of said valve for providing different charge pressure conditions effecting rapid movement of said valve into its wide open position.

6. In a blasting cartridge, a container having a charge receivnig chamber, a discharge orifice, a valve adapted to seal said orifice, fluid actuated means governing the position of said valve, and means automatically operative upon initiation of opening movement of said valve for causing said fluid actuated means suddenly to open widely said valve.

7. A blasting cartridge comprising a casing having a chamber for receiving a charge of high pressure air or gas, release means for said charge comprising a discharge control valve, pressure responsive means for eiiecting opening of said discharge control valve when a predetermined blasting pressure is attained within the cartridge and including a pressure actuated piston connected to said valve for holding the latter closed during building up of the blasting pressure within the cartridge and for opening said valve when said blasting pressure is attained, and means controlled by movement of said piston and rendered active upon initiation of movement of said valve toward its open position for accelerating movement of said piston suddently to move said valve into its wide open position.

8. A blasting cartridge comprising a casing having a chamber for receiving a charge of high pressure air or gas, release means for said charge.

means operative to eflect opening of said release means upon the attainment oia predetermined blasting pressure within the cartridge, and means .including frangible valve means adapted to rup- 5 ture upon initiation of movement of said latter means for accelerating movement of said last mentioned means toward its wide open position.

9. A blasting cartridge comprising a casing having a chamber for receiving a charge of high pressure air or gas and a control chamber, releasable valve means for discharging the blasting charge from said charge receiving chamber, a piston in said control chamber for controlling said valve means, means for supplying pressure fluid to-said control chamber, valve controlled passages 7 insaid piston'for supplying pressure fluid from said control chamber to saidcharge receiving chamber, means operative to eflect venting of said control chamber upon attainment of a predetermined blasting pressure within the charge receiving chamber, saidpassages in said piston being automatically closed when said control chamber is vented, and the pressure in said charge receiving chamber eflecting movement of said piston in said control chamber to release said valve means when'said control chamber is vented, and valve means automatically opened upon the initiation of opening movement of said first mentioned valve means for further and more freely venting said control chamber to efiect acceleration of movement'of said control piston to move suddenly said first mentioned valve means into a wide open position.

I 10. A blasting cartridge comprising a casing having a chamber for receiving a blasting charge,

and a control chamber, valve means for releasing the blasting charge from said charge receiving chamber, a piston in said control chamber for controlling said valve means, means for venting said control chamber to effect movement of said piston to release said valve means when a predetermined blasting pressure is attained within said charge receiving chamber, and means for automatically further and more freely venting said control chamber upon the initiation of opening movement of said valve means to accelerate opening movement of said valve means.

11. In a blasting cartridge, a container adapted -to receive a blasting charge and having a discharge orifice through which said charge may be released, a diiferential valve mechanism subject to a preponderance of fluid pressure in a closing direction when seated normally sealing said orifice when pressure exists within the cartridge, means for efiecting the opening of said diflferential valve mechanism when a predetermined pressure within the cartridge is attained, and associated means automatically operative to accelerate opening movement of said valve. 6G 12. A blasting cartridge, a container having a charge receiving chamber and a discharge orifice. a difierential valve for sealing said orifice, a control chamber for governing operation of said differential valve, means for venting said chamher to the atmosphere for initiating opening movement oi said valve, and means automatically operative upon initiation of opening movement of said valve for further and more freely venting said chamber to accelerate opening movement of said valve.

13. In a blasting cartridge, a container having a charge receiving chamber and a discharge oriflee, a differential valve mechanism for sealing said orifice when pressure in excess of atmospheric emsts in the cartridge, said cartridge embodying a control chamber, the pressure wherein governs the action of said differential valve mechanism, there being a passage extending from said control chamber to the exterior of said car- 5 tridge for venting the chamber to the atmosphere, means for venting said chamber to atmosphere to efiect initiation of opening movement of said valve mechanism, and an element rupturable upon the initiation of opening move- 10 ment of said valve mechanism for further and more ireeLv venting said chamber to accelerate opening movement of said valve mechanism.

14. A blasting cartridge comprising a casing having a chamber for receiving a blasting charge 15 and a control chamber, valve means for releasing theblastingcharge from said charge receiving chamber, a piston in said control chamber for controlling said valve means, means for venting said control chamber to efl'ect movement of said 20 piston to initiate opening movement of said valve means, and means automatically operative upon initiation of opening movement of said .valve means for further and more freely venting said control chamber to accelerate opening movement 25 of said valve means, said latter means including a frangible element.adapted to be broken to vent the control chamber, and an element actuated by said piston for breaking said frangible element.

15. A blasting cartridge comprising a casing 30 having a chamber for receiving a blasting charge and a discharge orifice, a valve for closing said orifice, controlling means for said valve governable to efiect exertion of a valve closing and holding pressure on said valve or to effect relief of 35 said pressure to eifect'valve opening upon attainment of any one of a wide range of blasting pressures in said chamber, and means operative automatically upon predetermined opening movement of said valve to effect complete relief of said 40 holding pressure.

16. A blasting cartridge comprising a casing having a chamber for receiving a blasting charge and a discharge orifice, a valve for closing said orifice, a charging line for said chamber, con- 45 trolling means for said valve governable upon supply of charging pressure through said charging line to close and maintain closed said valve and operative on a predetermined reduction of pressure in said charging line to efiect valve 50 opening, and means operative automatically upon such predetermined reduction in pressure in said charging line to provide an accelerated reduction in such pressure.

1'7. In a material breaking device, the combina- 55 tion of a container adapted to be charged with high pressure gas at a material breaking pressure and having an outlet therefor, differential valve mechanism controlling said outlet for releasing the charge of material breaking pressure into the 50 material to be broken, a control pocket for governing said difierential valve mechanism, and means for reducing pressure in said pocket to cause initial opening movement of said differential valve mechanism, said container having an exhaust port normally sealed from said pocket but communicable therewith consequent upon opening movement of said valve mechanism.

18. In a material breaking apparatus, the combination with a blasting cartridge having a casing in which a charge of gaseous medium is stored at high pressure and embodying means for releasing suddenly the charge including a valve, and controlling means for said valve including a 4- a,oss,7o7 control chamber which is filled with high pressure gaseous medium while the casing is charged and comprising a vent valve, and means for opening adapted to bevented to etfectopening of saidvalve, said vent valve actuated by the pressure responpressure responsive means for actuating the valve sive means. 5 located in the control chamber, and means for eflectlng quick venting of such control chamber ALLYN HARRIS. 6 

